The present invention relates to a chip resistor and a method of making the chip resistor. There are many conventional chip resistors, for example, a chip resistor in Patent Literature 1. In the chip resistor of Patent Literature 1, a resistor is formed on an upper surface of a substrate, and back electrodes are formed at two ends of a lower surface of the substrate and electrically connected to each end portion of the resistor. The back electrodes are typically formed by metal glaze containing Ag.
A chip resistor is mounted on a circuit board by solder material. FIG. 28 is a cross sectional view showing a conventional chip resistor A100 mounted on a circuit board 101. In FIG. 28, the chip resistor A100 is mounted on a wiring pattern 102 of the circuit board 101 by solder material 103. If there is a significant difference between thermal expansion of the circuit board 101 and thermal expansion of a substrate 1 of the chip resistor A100, in the case of applying a temperature cycle, stress resulting from the thermal expansion difference is applied on the solder material 103, causing a crack 104 on the solder material 103. Particularly, when the chip resistor A100 (substrate 1) is larger, the more stress is resulted from the thermal expansion difference, such that the possibility that a crack 104 occurs is higher. A large chip resistor A100 (3.2 mm×1.6 mm, for example) is used in automotive applications, and thus the crack 104 should be concerned.